| Of these, one of the largest is the parasphenoid which, in Ichthyopsids, is found underlying the basicranial axis. |
| In front of the presphenoid the basicranial axis is continued by the mesethmoid. |
| Some of the most important structural features that mark it as such are in the basicranial region. |
| The basicranial circulation of Ptomacanthus resembles that in arthrodire placoderms. |
| The basicranial axis is straight, and the fontanelle in the lachrymal region is very large. |
| The basicranial articulation was no longer the anchor for the palate, and the palatoquadrate was functionally replaced by its dermal anlagen, the maxillae. |
